The invention relates to a joint bridging device comprised of one bridging unit and two anchoring units connected to the respective longitudinal sides of the bridge unit. The anchoring units are each provided on their longitudinal side facing the bridging unit with a laterally open groove which the bridging unit engages.
In such an arrangement, known from German DE-P No. 35 29 877, the bridging unit consists of two bridging parts which can be pushed into each other in the manner of a telescope, in a direction perpendicular to the longitudinal joint extension one part of which, in cross section, is shaped like a tuning fork. This part accepts between its shanks the other which in cross section is shaped rectangularly. The outer margin strips of the bridging parts facing away from each other are shaped like cylinders and are supported in correspondingly halfshell-shaped grooves of the anchoring units.
With the known arrangement not only the bridging of a joint changing in widths between two structural parts can be maintained but also a leveling compensation can take place if, for example, the connected structural parts forming a floor shift relatively to each other in a vertical direction. While the anchoring units are rigidly connected at the longitudinal joint margins with the particular structural parts, the bridging unit can only execute a swiveling motion about the center axis of the bearing shells formed by the grooves in the anchoring units, if the structural parts change their level relative to each other. Thereby a relatively smooth transition from the surface of a structural part to that of another is achievable. Following a change of the joint width the bridging action is maintained so long as the bridging parts remain more or less deeply telescopingly engaged.
Depending on the cross sectional thickness of the bridging parts a more or less pronounced step is perforce generated in the region of the transition from one structural part to the other. In order to be able to keep the height of such a step at a minimum it is known from German DE-OS No. 30 15 011 to dimension the cross section thickness of the bridging parts in such an arrangement smaller than is required by the moment of flexion expected from the loads. To permit use of the arrangement in highly stressed areas such as in floors of storage halls, supermarkets and others, having floor areas carrying wheel loads of fork lift stackers or the like without deformation of the bridging parts, the known arrangement provided for a support rail fixedly clamped in at one of the longitudinal joint margins through which at least one bridging part is underpinned. In order to take changes of the joint width into consideration the support rail can be fixedly clamped to one marginal strip and may only extend over the minimum joint width to be expected. Consequently, the laterally freely projecting support rail must be able to accept an increased stress with the incnreasing joint width which results from the load being introduced in the region furthest removed from the clamping side. The moment of flexion resulting therefrom requires not only a support rail with correspondingly large section modulus but also clamping means which resist the leverages to be expected.
In a bridging arrangement known from German DE-P 31 51 516 the bridging parts are stabilized by a support rail which is slid bilaterally with one longitudinal margin strip in each instance into a groove which is provided in the bridging parts themselves. Springs which at both sides are clamped between the support rail and the bottom of the grooves hold the support rail always in the center of the joint independently of the state of width of the joint. While the bridging parts rest with undersides on the support rail, the upper side of the bridging parts forms a common tangent to both of their cylinder-shaped margin strips held in the bearing shells. Since, lastly, the bridging parts in the area of their interlocking margin strips have fret-shaped edges in horizontal projection and are congruent, so that with the teeth of the one bridging part, meshing with tooth gaps of the other bridging part, continuous steps in the transition region of the bridging parts can also be avoided. Instead, however, depending on the state of width of the joint, breaches of greater or lesser size corresponding to the parts of the tooth gaps are not filled out by teeth. Accordingly water and dirt can penetrate into this construction whereupon the durability and the ability to function are considerably impaired. A sealing of the described construction can, however, only be achieved with considerable additional expenditures and the sealing effect can only be provided below the interlocking bridging parts which remain unprotected even after the expensive sealing measures.